Conventionally, various spectrum determination are used in quality control of products in food and pharmaceutical fields. For example, spectrum determination methods such as a method which compares one reference spectrum (standard spectrum) of a known substance stored in a library with one spectrum of a target sample to confirm denaturation of the target sample, and a method which measures the reference spectrum multiple times, takes dispersion thereof into consideration, and compares the reference spectrum and the spectrum of the target sample to consider the statistical difference between the two are known.
Such device and method for determining a spectrum are used in cases where denaturation of protein is confirmed by comparing the intensity and the shape of protein spectrum (by comparing the intensity and the shape of normal protein as a reference and denatured protein).
Although characteristic (and tendency) of a spectrum can be reproduced by measuring the reference spectrum multiple times, an exactly same spectrum cannot be reproduced due to effects of random noises and the like in actual measurement. Therefore, efficient determination was difficult in spectrum determination which uses conventional spectrum measurement, and reliability of determination result was limited. Patent Literature 1 discloses a method for detecting a peak position of an optical spectrum. The method comprises: performing even-order differentiation of the optical spectrum; and weighting the obtained differential spectrum and the original optical spectrum respectively to obtain a mixed spectrum by adding or multiplying the two by corresponding points. Thus, numerous sharp and high (deep) peak positions in the optical spectrum can be efficiently detected at once.